This invention relates to woodworking machines, as exemplified by apparatus known in the industry as a log-slabbing chipper.
A log-slabbing chipper typically includes a power-rotated head disposed to one side of a support for a log. The head supports knife structure on its periphery which operates on rotation of the head to chip-off wood material on a log with relative movement of the head with respect to a log thereadjacent. The knife structures on the chipper head are rotated against a side of the log to produce the chipping action. Each knife structure includes one edge portion (a chip-cutting edge portion) which extends axially along the power-rotated head which functions to cut off the major portion of the chips produced by the apparatus as the edge portion is rotated and moved along a side of a log. In a typical log-slabbing chipper, this edge portion extends axially and also slopes inwardly toward the axis of the head, so that the edge portion moves in a conical path. Other chippers are known where the edge portion as described moves in a substantially cylindrical path.
A knife structure may further include what is sometimes referred to as a planing edge portion, which moves in a plane disposed perpendicular to the rotation axis of the chipper and which produces a flat surface on the log being processed as chips are cut off by the action of the chip-cutting edge portions in the knife structures. In addition to producing a flat surface on the log being processed, it is economically advantageous if the planing edge portions just described also produce useable chip material while performing the cutting action desired.
In log-slabbing chippers heretofore known, the flat face produced in the log as a result of the chipping action typically has not been truly smooth, meaning that the face has to be further processed if the face is to be present in a finished piece of lumber.
Thus, a general object of this invention is to provide improvements in a log-slabbing chipper with knife cutting edges present functioning to produce greater smoothness in the flat face of a log processed by the chipper than possible with prior known constructions.
Another object is to provide a chipper which produces greater smoothness in the flat face cut in a log, and which utilizes cutting edges operable to produce useful chip material while at the same time producing the smoothness required in the surface.
It is recognized that for maximum utility, a degree of flexibility is desirable in the operation of a chipping head. Further explaining, in certain operations the degree of smoothness obtained in the finish of a face in the log need not be as great as in other types of operations. In fact, some lumber users might even desire a rough cut, or sawn appearance in the finish of a log, as the result of the chipping action. To obtain different surface characteristics when a log face is being processed, the log-slabbing chipper of the instant invention features removable and replaceable end-cutting structures at the work-confronting face of the chipper, which affords a relatively easy method of obtaining different types of finish in the product processed, depending upon the type of cutting structure which is placed in operative position at the work-confronting face of the chipper.
A further object of the invention, therefore, is to provide a log-slabbing chipper which is modifiable in a relatively simple manner to obtain different types and styles of finish in the flat face produced by the chipper when such is operated.
A further feature and object of the invention is to provide an improved log-slabbing chipper which relies upon replaceable double-edged knives for producing the cutting action in the chipper. With dulling of a knife edge, a double-edged knife is easily turned about to present an opposite cutting edge for cutting purpose. With both edges in a knife dulled through use, a knife may be easily removed and replaced with a knife having sharpened edges. With presharpened double-edge knives, far greater accuracy is obtainable in the positioning of a cutting edge.